Electric power is generally transmitted from generation plants to end users (industries, corporations, homeowners, etc.) via a transmission and distribution grid consisting of a network of power stations, transmission circuits, and substations interconnected by powerlines. Once at the end users, electricity can be used to power any number of devices. The transfer of alternating-current (AC) electric power to the end users most frequently takes the form of three-phase electric power, where three current waveforms are produced that are generally equal in magnitude and 120° out of phase to each other. If the load on a three-phase system is balanced equally among the phases, no current flows through a neutral point, which is an important design aspect of the electric grid, allowing for efficient use of transformer capacity, reduced materials (e.g., size of a neutral conductor), etc. However, there are many factors that may create imbalance between the phases, such as excess load usage, downed powerlines, etc.
The topology of the electric transmission grid typically considers the balancing of the three-phase system, such that each end user (and thus the end user's devices) is attached to the grid via a particular phase's current waveform (though certain customers may be connected to two or three phases of the grid). Most often, however, the end users, and more specifically the end users' devices, are unaware of which phase they are operating upon. Accordingly, there is no phase-based control of the devices beyond planning the physical topology of the grid, which is difficult (and often expensive) to change once it is installed.